Improvement in self-binding pulley-blocks



UNITED STATES PATENT OFFICE.

JAMES BIRD, OF NAUGATUCK, CONNECTICUT.

IMPROVEMENT IN SELF-BINDING PULLEV-BLOCKS.

Specification forming part of Letters Patent No. l 52,270, dated June23, 1874 5 application led May 2c, 1874.

To all whom it may concern:

Be it known that I, JAMES BIRD, of Naugatuck, in the county of New Havenand State of Connecticut, have invented a new and Improved Self-Bindin gPulley-Block, of which the following is a speciication:

Figure l is a sectional face view of .my iinproved pulley-block, onecheek ofthe shell being cut away to display the sheave and channel. Fig.2 is a similar view of the apparatus, showing the sheave raised againstone end of the channel. Fig. 3 is a central cross-section of theapparatus.

Similar letters of reference indicate corresponding parts'in all the`figures.

The object of this invention is to produce a pulley-block with a sheavecapable of an eccentric movement, so that by means of the sheave therope can be clamped in any desired position, leaving the weight on therope suspended at the desired height for a suitable length of time.' Theinvention consists in hanging an annular sheave loosely upon a coa-k orbushing, which is fitted eccentrically upon the pintle, and capable ofturning around the latter. The coak or bushing is connected with a leverpivoted to the pintle, so that it can be turned by means of said leverto bring the edge of the sheave concentric to or eccentric with thecencave edge of the cam. The rope will be free to play on and with thesheave as long as the same is concentric to said cam; but when it isdesired to bind the rope, the lever is swung to carry the sheave nearone end of the cani, and there bind the rope and hold it secure.

O11 the accompanying drawing, the letter A represents the shell of thepulley-block, composed of two cheeks, a a, and of a cam, b, between saidcheeks. The cam is irmly secured in the shell and the cheeks are heldtogether by means of bolts, straps, rope, or otherwise. B is the pintle,having its bearings in the cheeks of the shell, and, by preference,secured so it cannot revolve. C is the coal: or bushing, hung upon thepintle between the cheeks a a, and capable of turning loose on the saidpintle. This coal; or bushing is of cylindrical form, but boredeccentric, so that its periphery is eccentric to the axis of the pintle.D is the sheave or wheel, made of annular form, its in ner peripherycorresponding in diameter t0 the outer periphery of the bushing O. E isa lever, pivoted to the pintle outside of the shell, and connected witha pin, d, that projects from one face ofthe bushing through a curvedslot in one of the cheeks a, said slot being indicated by dotted linesin Figs. l and 2.

Ihile the parts are in the position indicated in Fig. l-that is say,while the sheave is concentric to the concave edge of the cam b thechannel c for the rope F will be free, and the rope consequently free,to be drawn in either direction on and over the sheave, which will rollon the bushing.

Vhen it is desired to hold the weight on the rope F suspended at acertain height, the lever E is swung by means of a ha1'1d-line,f, orotherwise, to turn the bushing C and bring the sheave into the positionshown in Fig. 2. In this position the sheave will bear against one endof the cam b, as shown, and will thus bind and rmly secure the rope F inposition.

It is evident that this invention will also apply where the pintle B isdispensed with, and a projecting bearing onthe bushing eccentric to itscircumference used instead also when, in place of the lever E, a cord isused, connecting with the pin cl, and passing Over a friction-rollerthat may be hung to the shell.

As to the cam b, it is not imperatively necessary that it have theconcave form shown, as long as one end of it is in the positionindicated, to aid in binding the rope.

I claim as my invention and desire to secure by Letters Patentl. Theannular sheave D, itted upon an eccentric coak or bushing, G, so that itmay serve for binding the rope, as described.

2. rllhe combination o't the lever E with the eccentric bushing C andannular sheave D of a pulley-block, and with the cam b ofthe shell, asspecified.

The above description of in y invention signed by me this 25th day ot'May, 1874.

J AMES BIRD.

Yitn esses:

A. V. BRIEsEN, F. V. BRIEsEN.

